Childhood Cancer In Chinese Children and Family Cohorts We are conducting two pilot studies to test the feasibility of (1) follow and participation in interviews of a sample of 500 families from two county sites where the Community Intervention Program (CIP) was carried out in the mid-1990s and (2) identification of incident pediatric cancers arising among thoseborn during 1994-96 in hospitals serving the CIP population and ability to link these pediatric cancer patients back to the CIP population. The CIP community intervention program trial, which was carried out during 1994-96 in three large counties northeast and south of Beijing, evaluated the effectiveness of periconceptional folic acid supplements in reducing neural tube defects. There were dramatic reductions in neural tube defects among offspring of mothers who took folic acid supplements during the periconceptional period. Publications from case-control epidemiologic studies in the past 10 years from Western countries have shown that periconceptional folic acid supplements may reduce risks of pediatric leukemia and potentially other pediatric cancers in offspring of mothers who take these supplements. Other studies have shown statistical associations with periconception folic acid and other serious chronic diseases of offspring including asthma. The pilot studies will attempt to trace, enroll, and interview 500 families from Taicang, Jiangsu Province and Laoting, Hebei Province and will seek to identify all pediatric cancers diagnosed during 1994 to the present among children born during 1994-96 and link these children back to the CIP cohort.